U.S. Pat. No. 3,456,420 issued July 22, 1969 discloses an arrangement in which a wrapper type blank is tightened about a group of articles by means of a fixed bar which is arranged to engage portions of a wrapper and to impart a tightening action thereto as a group of articles and the associated wrapper are moved along a predetermined path. One objection to this type of tightening mechanism centers around the fact that a substantial frictional force is imparted to the wrapper as it moves along due to frictional contact between the wrapper and the static tightening bar.
U.S. Pat. No. 4,285,185 issued Aug. 25, 1981 discloses apparatus for tightening a wrapper blank about a group of articles and for positioning the articles relative to the blank. This arrangement constitutes pivotally mounted elements arranged to move alongside an article group and its associated wrapper and the movement thereof is timed so that the pivotally mounted elements are arranged to enter apertures in the side walls of the wrapper. An objection to this arrangement resides in the fact that precise timing of the movement of the pivotally mounted tightening elements relative to the movement of the article group and associated wrapper is required. Of course if timing becomes insufficiently precise due to wear or for any other reason, costly shut downs and package damage may result. This arrangement provides means for pulling the wrapper downwardly only.
U.S. Pat. No. 4,237,673 issued Dec. 9, 1980 and owned by the assignee of this invention discloses an arrangement in which a plurality of movable metering bars are arranged to cooperate with angularly disposed guide means in such a manner as to meter a group of primary packages into the open ends of a sleeve type wrapper disposed between the metering bars and movable therewith. This arrangement provides an efficient means of loading an open-ended wrapper from both ends but is not well suited for use in conjunction with wraparound type packages.